A question about spindle sync
- markd
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12 Nov 2018 18:29 #120501
by markd
A question about spindle sync was created by markd
I have a spindle set up as an A axis and would like to cut threads. The motor is a nema23 stepper with 3600 pulses per rev. My question is can I feed the astep into the encoder.0.phase-A and use a hall effect sensor for encoder.0.phase-Z?
The max spindle rpm would be about 500 which equates to 1.8khz. I could use a binary counter to scale the 1.8khz down if necessary.
The max spindle rpm would be about 500 which equates to 1.8khz. I could use a binary counter to scale the 1.8khz down if necessary.
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- tommylight
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12 Nov 2018 22:10 #120516
by tommylight
Replied by tommylight on topic A question about spindle sync
It should be possible, but using a stepper as a spindle is not preferred for anything over 200 RPM.
Stepper motor have a lot of torque at low speeds, but very little at high speeds, and 500 rpm is high for them.
Have a look at the torque chart, the torque line drops like a rock beyond 200 rpm.
The config for it should be set in velocity mode and have encoder feedback to Linuxcnc, so pretty easy to set up.
Do give it a try and report back how it works, as i never did try that.
Stepper motor have a lot of torque at low speeds, but very little at high speeds, and 500 rpm is high for them.
Have a look at the torque chart, the torque line drops like a rock beyond 200 rpm.
The config for it should be set in velocity mode and have encoder feedback to Linuxcnc, so pretty easy to set up.
Do give it a try and report back how it works, as i never did try that.
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- andypugh
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13 Nov 2018 15:03 #120549
by andypugh
Replied by andypugh on topic A question about spindle sync
You probably don't actually need an encoder counter, it should be possible to do something clever with the stepgen position feedback.
This probably needs a custom HAL component that emulates index-enable behaviour while resetting an offset inside the component.
input pin -> stepgen.N.position-fb
io pin -> index-enable
output pin -> spindle-position
internal-data -> offset modulo full-turns.
This probably needs a custom HAL component that emulates index-enable behaviour while resetting an offset inside the component.
input pin -> stepgen.N.position-fb
io pin -> index-enable
output pin -> spindle-position
internal-data -> offset modulo full-turns.
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